The present invention relates generally to chemical mechanical polishing of substrates, and more particularly to an apparatus for moving a cassette in a polishing station.
Chemical mechanical polishing (CMP) is one method of planarizing substrates. This planarization method typically requires that the substrate be mounted on a carrier or polishing head in a CMP apparatus. The exposed surface of the substrate is placed against a rotating polishing pad and a polishing slurry is supplied to the polishing pad. The interaction of the polishing pad, slurry and substrate results in polishing.
Substrates are typically transported in cassettes between different stations in an integrated circuit fabrication process. As such, the substrates may be exposed to contaminants when they are moved, for example, to and from the polishing station. For instance, the substrates may be exposed to contaminants when lowered into a holding tub which stores the cassettes before polishing.
Thus, there is a need to quickly move cassettes into and out of a polishing station with minimal risk of contaminating the substrates.